1. Field of the Invention
The present invention relates to a depth sensitive diver safety system to be utilized by scuba divers in order to actively reduce the likelihood that a diver will inadvertently descend beyond an acceptable depth limit for the diver, or run out of air while beneath the water's surface.
2. Description of the Related Art
Scuba diving is a widely enjoyed recreational activity which while it can facilitate a variety of enjoyable activities such as, hunting, photography and exploration, has many attended dangers associated therewith. Fortunately, most common dangers associated with scuba can be avoided if appropriate care is taken. The most common avoidable dangers associated with diving are generally related to the limited air supply carried by a diver and the hazards associated with exceeding acceptable depth limitations for the diver.
Usually, the diver's air supply is contained entirely within one or more pressurized tanks carried on the back of the diver. Further, while the size and type of tank is the important factor in determining the amount of air which a diver has available for use beneath the water, it is the individual diver's rate of consumption which determines the amount of time for which a diver can stay under water.
A diver's rate of consumption will primarily be affected by the individual diver's physical attributes and level of activity, as well as the depth at which the diver is swimming. Specifically, as the swimming depth of a diver increases, the increased pressure at the depth, and particularly the increased pressure at which the breathable air is being supplied to the diver, will substantially increase such that a larger quantity of air will be drawn into the diver from the tank with every breathe. As such, a diver with the same equipment and breathing rate as a diver who remains closer to the surface will run out of air substantially faster due to the larger amounts of air being drawn in. Further, not only will the diver at depth run out of air faster, but this same diver will also require more time to ascend and therefore more air in order to properly return to the surface.
The need for a diver to properly and preferably slowly return to the surface when scuba diving is extremely important to ensure that a variety of possibly serious problems do not occur. One such problem is the risk of a pulmonary embolism which can result if a diver ascends too rapidly without appropriately exhaling and releasing expanding air from his lungs, as often happens in a panic situation after a diver begins to run low or is out of air. Specifically, at increased depth, the pressure is greater and the air within the lungs is compressed, but as the diver surfaces that air considerably expands and must constantly be released. For example, the volume occupied by a quantity of air at thirty-three (33) feet below the surface is only half of the volume occupied by the same quantity of air at the surface. Therefore, divers must ascend at a relatively slow rate and during deeper diving make equalizing stops along the way, all of which requires greater quantities of reserved air to arrive at the surface when the diver is deeper and the air tank begins to run low of air.
Presently, most divers will utilize various gauges which indicate the air pressure remaining in the tanks, and to ensure safety they are instructed to check those gauges frequently in order to detect a low air supply. Nonetheless, when divers become involved in various activities beneath the water, many of which will not only divert their attention but will also increase their rate of air consumption, they can loose track of time and a rate of air depletion, therefore not realizing that they are low on air until it is dangerously late. This is particularly the case in underwater rescue operations wherein rescue divers are involved in strenuous operations. Further, even if a diver wanted to check the gauges frequently, if it is dark, they are swimming in silty water or visibility conditions are otherwise impaired it is often impossible or very difficult to effectively check the gages.
In the past, other types of valve mechanisms known as "J" valves had been implemented in an attempt to increase safety. These "J" valves, which are now rarely utilized due to dangerous design problems, were generally designed to maintain a constant 300 psi air reserve available to a user if air runs low. The "J" valves, however, maintain a constant reserve and do not provide the greater reserve of air which will be required at a greater depth. Also, J valves act passively and necessitate that the diver be aware of the danger and perform some often difficult manipulations in order to implement the reserve and surface. Therefore, their is still a substantial need in the art for a system which incorporates a device that even when the diver is distracted and unaware of their current air circumstance, or even unconscious, will actively and effectively function to alert the diver and act to ensure that the diver returns to the surface with sufficient air. In particular, it is necessary to have such a device which determines when the diver is running low on air, in accordance with the depth of the diver, thereby ensuring that a sufficient reserve to correspond safe surfacing from the diver's depth is maintained, while also actively causing the diver to gradually begin surfacing to safety.
Another major diving concern and a frequent reason for diving accidents and deaths is the depth at which a diver swims. Specifically, individuals underneath the water's surface absorb oxygen and nitrogen into their body after prolonged periods of breathing air regulated to be breathable at substantial depths. Pure oxygen, as used in military rebreather units, if absorbed at only 33 feet causes oxygen poisoning, seizures, unconsciousness and probably death. Nitrogen, when introduced to the body, can also lead to some dangerous situations, namely, nitrogen narcosis and decompression sickness, often referred to as the bends.
Nitrogen narcosis primarily involves a drunken state which the diver enters when a safe depth is exceeded without an appropriate air mixture, and can result in poor judgment, disorientation or unconsciousness. Accordingly, a diver affected by nitrogen narcosis may not recognize that they are running low on air and/or may act recklessly and dangerously doing things such as swimming even deeper, and/or removing their mask, regulator and/or air tanks. Although dangerous, nitrogen narcosis is also very easily prevented if a diver maintains appropriate depth levels. Further, if nitrogen narcosis symptoms are experienced a diver must merely swim to a shallower depth to regain normal cognoscence.
Regarding the bends, it results from prolonged exposure at substantial depth without taking proper preventive safety measures, and primarily involves the accumulation of excess nitrogen in the body. Specifically, at depth extra nitrogen is absorbed by the body. This extra nitrogen, which exits the body gradually, must not exceed acceptable limits within the body or serious trauma can occur. Generally, this problem is avoided through the diver's use of various charts and tables which help calculate the maximum safe duration for a dive at a particular depth. Unfortunately, however, divers involved in certain activities such as hunting or exploring may lose track of their depth and may accidently descend to a deeper area which disrupts their calculations regarding the maximum duration of the dive. The erroneous calculations may not only cause problems to the diver on that particular dive, but if they plan to make a series of dives can lead to problems on a future dive, even if that future dive is a relatively shallow dive.
As such, it would be highly beneficial in circumstances of oxygen poisoning, nitrogen narcosis and decompression sickness, to provide a diver safety system which will actively function to prevent a diver from exceeding an appropriate preset swimming depth. Such a device could function to ensure that the maximum depth limits, which are set for very important safety reasons, are maintained, and if a diver inadvertently or intentionally exceeds those limits, that active steps will be taken to gradually return the diver to an appropriate depth. The device of the present invention is designed specifically to meet the needs present in this specialized art through a system that can be easily incorporated and/or built into existing scuba equipment in order to eliminate some degree of human error involved in many dive accidents and deaths. Presently, the devices known in the art merely enable only conscious, level headed divers to be alerted of potentially hazardous conditions, but do not function actively to prevent a diver who does not notice, or care about these alarms from inadvertently exceeding appropriate depths and air limits.